In the small hours of the longest night, the moon shone on snow and all the frost needles in trees and fences blown there by the breath of fog. It was a light of ethereal greys, infinite in their variety – a momentary world of cold magic. The moon rolled west and it took me too long to follow it. Between waking to see the moonlight and the alarm going off, I had a dream – a dark story which evaded capture by words. Without moonlight, I set off across the snow with a stick, followed the fox up Windmill Hill, and crossed roads and fields to the stile with a western view at wood's edge.

Buildwas power station droned, generating electricity for a grid straining under the pressure of the cold spell, and its plume of darker grey spread westward into the fog. There was a deeper darkness there, where the moon should be, where my unspeakable dream went. Somewhere west-north-west was the first lunar eclipse on the winter solstice for 400 years. What happened the last time, back in 1610? Did people stand here watching the slow shadow of the earth crossing the moon, turning it red? What did they think it was? Galileo discovered the moons of Jupiter in that year but I doubt anyone standing here then knew that. Could they see these "new" bodies in the night sky?

For thousands of years, the winter solstice had been a kind of gateway between life and death opened by that beam of light which came from the first ray of sunlight on the dawn of the new year at the solstice. In stone circles and burial sites around Britain, I imagined hardy souls, huddled against the gnawing cold, waiting for the alignment of stones set 5,000 years ago to let first light touch something beyond words. But what would the ancient people have made of a lunar eclipse on the same night? If they had my luck, not much.

The sea of fog had swallowed the moon. Peachy glows there were reflections of town street lights. An aeroplane hummed above, searching for a snow-free runway. A tawny owl hooted through the wood, searching for something bloodier. I looked down the Edge to a village stirring in the dark: lights catching a gallery of white trees; a car heading up the hill; a blackbird chuk-chuking across gardens. This village would not see the sun until Valentine's Day. Over the Edge to the north-east appeared almost luminous slashes of sea-green light as dawn split through cloud and turned the snow pale blue; it was the shortest day.